Today is ?-Day 2008. A day in honor of ?, one of the most impor­tant math­e­mat­i­cal con­stants. It approx­i­mately equal to 3.14. ? rep­re­sents the ratio of any circle’s cir­cum­fer­ence to its diam­e­ter in Euclid­ean geom­e­try, which is the same as the ratio of a circle’s area to the square of its radius. For those who live in the US and use the MM/DD date rep­re­sen­ta­tion for­mat, the rea­son should be clear enough: March 14^th ? 3.14. On my knowl­edge the best ?-Day was in 1592 (3÷14÷1592 at 6:53:58 = 3.14159265358).

Coin­ci­den­tally, ?-Day is also the birth­day of Albert Ein­stein, who no doubt knew more than a lit­tle about ? :-)

14th March, 2008 View Comments

For years, researchers have been build­ing tiny nanobots that could one day serve a vari­ety of pur­poses. But, until now, nanobots couldn’t work together. Recently, sci­en­tists Anir­ban Bandy­opad­hyay and Somo­brata Acharya from the National Insti­tute of Mate­ri­als Sci­ence in Tsukuba, Japan, have built the first ultra-tiny, ultra-powerful “brain” for nanobots. The brain acts as tiny com­puter tran­sis­tor. But instead of car­ry­ing out just one oper­a­tion at a time, like a nor­mal tran­sis­tor, the new devices can simul­ta­ne­ously per­form 16 oper­a­tions at once. In other words, the devices use par­al­lel processing—like the human brain—rather than ser­ial pro­cess­ing (like a nor­mal com­puter). The researchers call this abil­ity “one-to-many” communication.

A machine assem­bly con­sist­ing of 17 iden­ti­cal mol­e­cules of 2,3,5,6-tetramethyl-1–4-benzoquinone (DRQ) exe­cutes 16 instruc­tions at a time. A sin­gle DRQ is posi­tioned at the cen­ter of a cir­cu­lar ring formed by 16 other DRQs, con­trol­ling their oper­a­tion in par­al­lel through hydrogen-bond chan­nels. Each mol­e­cule is a logic machine and gen­er­ates four instruc­tions by rotat­ing its alkyl groups. A sin­gle instruc­tion exe­cuted by a scan­ning tun­nel­ing micro­scope tip on the cen­tral mol­e­cule can change deci­sions of 16 machines simul­ta­ne­ously, in four bil­lion (4¹⁶) ways. This par­al­lel com­mu­ni­ca­tion rep­re­sents a sig­nif­i­cant con­cep­tual advance rel­a­tive to today’s fastest proces­sors, which exe­cute only one instruc­tion at a time.

Bandy­opad­hyay, A., Acharya, S. (2008). A 16-bit par­al­lel pro­cess­ing in a mol­e­c­u­lar assem­bly. Pro­ceed­ings of the National Acad­emy of Sci­ences, 105(10), 3668–3672. DOI: 10.1073/pnas.0703105105

12th March, 2008 Comments Off